Registers MMU (MMU3)

Starting from firmware 3.0.0, the Original Prusa Multi-material upgrade (MMU) has a set of runtime variables called registers. You can use these to read or write values into the MMU via G-codes. This article provides the list of available registers in the current firmware.

They can be different error codes and status information related to the MMU (e.g. filament errors, motor errors, temperature warnings, etc), specific parameters (feed rate, acceleration, current, etc), and different components (pulley, selector, idler, etc).

The table below includes 8-bit (empty value: 0xFFh 255) and 16-bit registers (empty value: 0xFFFFh 65535). The empty values show the maximum amount the register can hold.

There are three different access types:

• Read: the register can be only read.
• Write: the register can be read and written to. The written change is not persistent (applies only until the reset of the MMU).
• Write Persistent: the register can be read and written to. The written values are stored in EEPROM even after the MMU is restarted.

G-codes

Generally, the registers are in the MMU. One of the ways of reading/writing into the registers is through G-codes. The ones you will need here are:

• M707: Used to read values from specific addresses (e.g., the version, current error codes, filament state).
• M708: Used to write values to specific addresses, allowing for changes in various printer parameters.

{"serverDuration": 150, "requestCorrelationId": "3ba2ba4e4dc94b4c"}